Membrane seal for water heater tank spuds

ABSTRACT

A method of manufacturing a water heater includes the steps of providing a water heater tank having an interior and an exterior, the tank also including a first aperture communicating between the interior and exterior, providing a spud having an internally threaded aperture and placing a membrane between the spud and the tank such that the membrane covers the first aperture. Thereafter, the method also includes the steps of welding the spud and the membrane to the tank, and thereafter forming a second aperture in the membrane so that the threaded aperture of the spud communicates with the interior of the tank via the first and second apertures.

BACKGROUND

The present invention relates to a water heater and a method of manufacturing the water heater

SUMMARY

In one embodiment, the invention provides a method of manufacturing a water heater, the method comprising: providing a water heater tank having an interior and an exterior, the tank also including a first aperture communicating between the interior and exterior; providing a spud having an internally threaded aperture; placing a membrane between the spud and the tank such that the membrane covers the first aperture; thereafter welding the spud and the membrane to the tank; and thereafter forming a second aperture in the membrane so that the threaded aperture of the spud communicates with the interior of the tank via the first and second apertures.

In another embodiment, the invention provides a method of manufacturing a water heater, the method comprising: providing a water heater tank having an interior and an exterior, the tank also including a first aperture communicating between the interior and exterior; providing a spud having an internally threaded aperture; placing a membrane between the spud and the tank such that the membrane covers the first aperture; thereafter welding the spud and the membrane to the tank; thereafter spraying unfired glass to the interior of the tank; thereafter applying heat to the unfired glass; thereafter pressure testing the interior of the tank with the membrane covering the first aperture; and thereafter forming a second aperture in the membrane so that the threaded aperture of the spud communicates with the interior of the tank via the first and second apertures.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a water heater embodying the invention.

FIG. 1B is an enlarged portion of the water heater in FIG. 1A.

FIG. 2 is an exploded view of a spud, a membrane and a portion of the tank in FIG. 1A prior to a welding process.

FIG. 3A is a section view of the spud, membrane and portion of the tank in FIG. 2 in position for the welding process.

FIG. 3B is a section view of the spud, membrane and portion of the tank subsequent to the wending process.

FIG. 3C illustrates the elements in FIG. 3B plus a coating on the interior of the tank.

FIG. 3D is a perspective view of the elements in FIG. 3C with a portion of the membrane removed.

FIG. 4 is a flow diagram illustrating one method of manufacturing the water heater in FIG. 1A.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

FIGS. 1A and 1B illustrate a water heater 10 according to one embodiment of the present invention. Particularly, FIG. 1A illustrates the water heater 10 including a base pan 15, a metal water tank 20 with a bottom head 22, an insulating jacket 25 surrounding the tank 20, and insulating material 27 between the outer surface of the tank 20 and jacket 25. The top of the jacket 25 is cut away to show the insulation 27. The water heater 10 also includes a burner 30 disposed in a combustion chamber 32 beneath the bottom head 22 of the tank 20, a water inlet pipe 35, a water outlet pipe 37, and a flue tube 40 extending from the combustion chamber 32 and through the tank 20. During operation of the water heater 10, gas fuel is provided to the burner 30 through a conduit 45. Products of combustion or hot gasses flow up from the combustion chamber 32 and through the flue tube 40 to heat the water in the tank 20. Other constructions of the water heater also fall within the scope of the invention.

FIG. 1B illustrates a detailed portion of the water heater 10. Particularly, FIG. 1B illustrates a connection 50 between the inlet pipe 35 and the tank 20 according to one embodiment of the present invention. In the illustrated construction, the connection 50 is the same as a connection between outlet pipe 37 and the tank 20, thus the following description applies to both connections between either inlet pipe 35 or outlet pipe 37 and the tank 20. The connection 50 is defined by a spud 55 as further described below.

In the illustrated construction, the spud 55 is manufactured of a metal material. As illustrated in FIGS. 2 and 3A, the spud 55 includes a threaded inner surface 65 and a beveled lower portion 70. The threaded surface 65 defines an aperture 75 extending through the spud 55. A substantially circular membrane 60 is manufactured from a flat metal sheet having a substantially uniform thickness between about 0.002 inches and about 0.006 inches. The membrane 60 is located between the spud 55 and an exterior surface 85 of the tank 20 and has a periphery 80 extending outward of the spud 55 prior to a welding process, as further explained below. In other constructions, the membrane 60 can include different shapes and thicknesses based on desired specifications and manufacturing parameters of the water heater 10

FIGS. 2 and 3A-3D help illustrate the steps of a manufacturing process of the water heater 10 according to one embodiment of the present invention. With reference to FIGS. 2 and 3A, the manufacturing process includes providing the tank 20, one spud 55 and one membrane 60 to form one connection 50 (as illustrated in FIG. 1B). In the illustrated construction, the membrane 60 is placed between the spud 55 and a portion of the tank 20 defining an aperture 90, which connects the exterior and interior of the tank 20 (FIG. 3A). The spud 55 and membrane 60 are aligned with respect to the aperture 90 such that the membrane 60 is pressed between the lower portion 70 of the spud 55 and the exterior surface 85 of the tank 20. The membrane 60 substantially covers aperture 90 of the tank 20 and aperture 75 of the spud 55. In other constructions, the spud 55 and membrane 60 can be aligned differently based on desired manufacturing parameters of the water heater 10.

The manufacturing process also includes welding the spud 55 to the membrane 60 and tank 20, as illustrated in FIG. 3B. As a result of the welding process, at least part of the lower portion 70 of the spud 55, the periphery 80 of the membrane 60 and a portion of the tank 20 defining aperture 90 and adjacent the periphery 80 form a welding nugget 95. The membrane 60 welded between the spud 55 and the tank 20 separates the interior and exterior of the tank 20, thus sealing the aperture 90. In a preferred embodiment, the tank 20, spud 55 and membrane 60 are manufactured of a metal material. However, the invention provides for the tank 20, spud 55 and membrane 60 to include materials other than metals to facilitate other types of welding processes (e.g., ultrasonic welding). In one construction, the membrane 60 can further include a permeable material that permits a relatively small amount of fluid (e.g., air) to flow therethrough.

Subsequent to the welding process, the manufacturing process includes (see FIGS. 3B and C) applying a coating 100 to the interior surface 105 of the tank 20 to help prevent the tank 20 from rusting, as is known in the art. In one preferred construction, applying the coating 100 to the inner surface 105 of the tank 20 includes spraying unfired glass on the interior of the tank 20. In other constructions, applying the coating 100 to the interior of the tank 20 includes applying a coating of porcelain, ceramic, polymer, organic material, a lining formed by electroplating or other materials suitable to prevent the surface of the tank 20 from rusting. In the manufacturing process of the water heater 10, it is desirable to prevent materials forming the coating 100 to come into contact with or settle on the threaded inner surface 65 of the spud 55. Because the membrane 60 covers the aperture 90, the membrane 60 helps prevent the coating material 100 from contacting the threaded surface 65 of the spud 55, as illustrated in FIG. 3C.

Optionally, the manufacturing process can include applying a dust coating to the exterior surface 85 of the tank 20. In applying the dust coating, part of the material being applied also coats or comes into contact with the threaded surface 65 of the spud 55 and outer surface 110 of the membrane 60. The dust coating forms a relatively thin layer in comparison to the coating 100 applied to the interior surface 105 of the tank 20. However, the dust coating is sufficient to help prevent oxidizing of the exterior surface 85 of the tank 20 and the membrane 60, as further explained below. Because the dust coating forms a relatively thin layer in comparison to the coating 100, there is no detriment to the manufacturing process if the dust coating is formed on the threaded surface 65 of the spud 55. In some constructions, the dust coating is formed of the same material as the coating 100. However, in other constructions, the dust coating includes other materials that permit forming a relatively thin layer on the surface of the tank 20 and also help prevent oxidizing the tank 20 and membrane 60 surfaces.

Once the coating 100 is applied to the interior surface 105 of the tank 20, the tank 20 is put through a heating process. As indicated above, one preferred construction includes spraying unfired glass to form coating 100 on the interior surface 105. In this construction, the heating process includes placing the tank 20 through a furnace and heating/firing the unfired glass coating 100 to about 1600 degrees Fahrenheit. Firing the glass coating 100 allows fusing the elements forming the coating (e.g., silica and metals) to the surface 105 of the tank 20. As a result, the coating 100 is firmly fused to the surface 105 to help prevent rusting of the tank 20 during manufacturing and normal use of the water heater 10. The membrane 60 welded to the spud 55 and tank 20 is formed to withstand such temperatures. In other constructions, the membrane characteristics (e.g., diameter, periphery shape, thickness, material) can be adjusted for other heating processes that include heating the tank 20 to different temperatures.

Depending on the characteristics (e.g., materials and/or thicknesses) of the tank walls and membrane 60, the heating process can cause oxidation of the surface of the tank 20 and portions of the membrane 60 not protected by coating 100. In such cases, the dust coating helps prevent oxidation of the tank 20 and membrane 60, thus preserving the integrity of the tank 20 and membrane 60 during subsequent steps of the manufacturing process of the water heater 10.

The manufacturing process also includes pressure testing the tank 20 for detection of leaks or structural damage to the tank 20. In one process, the tank 20 is pressurized to about 35 pounds per square inch (psi). The membrane 60 welded to the spud 55 and tank 20 is formed to withstand such pressure, allowing proper testing of the tank 20. In other constructions, the membrane characteristics (e.g., diameter, periphery shape, thickness, material) can be adjusted to test the tank 20 at different pressures. In one preferred embodiment, the membrane 60 welded to the tank 20 prevents leaks or flow of fluid (e.g., pressurized air) therethrough. However, in other constructions the membrane 60 can include one or more relatively small apertures or a permeable material allowing fluid to flow therethrough. It is to be understood that for the purposes of pressure testing the tank 20, such characteristics of the membrane 60 are taken into consideration and are not detrimental to the testing process or manufacturing process in general of the water heater 10.

The heating process and pressure testing of the tank 20 can be done in a different order. For example, the tank 20 can be pressure tested prior to applying and firing the coating 100 to the surface 105 of the tank 20.

Once the tank 20 has gone through the heating process and has been pressure tested, the manufacturing process includes creating or forming an aperture through the membrane 60 to allow the flow of fluid (e.g., water) during operation of the water heater 10. In the construction illustrated in FIG. 3D, a hole saw (not shown) is utilized to remove at least a portion of the membrane 60 for forming aperture 115. The hole saw may be inserted through aperture 75 of the spud 55 or applied to inner surface 120 of the membrane 60. In another construction, a perforating element is inserted through aperture 75 of the spud 55 with a sufficient amount of force to rupture the membrane 60 without removing a portion of the same.

FIG. 4 is a flow chart illustrating an exemplary process for manufacturing the water heater 10. It is to be understood that some of the steps comprised in the following process can occur in a different order. The process includes providing a water heater tank having an aperture communicating the interior and exterior of the tank (step 200), providing a spud with a threaded aperture (step 205) and placing a membrane between the spud and the tank such that the membrane covers the aperture of the tank (step 210). The process also includes welding the spud and the membrane to the tank (step 215), spraying a coating, such as unfired glass, to the interior of the tank (step 220) and applying heat to the coating (step 225). Finally, the process includes pressure testing the tank with the membrane covering the aperture of the tank (step 230) and forming an opening in the membrane for allowing fluid flow therethrough (step 235).

Various features and advantages of the invention are set forth in the following claims. 

1. A method of manufacturing a water heater, the method comprising: providing a water heater tank having an interior and an exterior, the tank also including a first aperture communicating between the interior and exterior; providing a spud having an internally threaded aperture; placing a membrane between the spud and the tank such that the membrane covers the first aperture; thereafter welding the spud and the membrane to the tank; and thereafter forming a second aperture in the membrane so that the threaded aperture of the spud communicates with the interior of the tank via the first and second apertures.
 2. The method of claim 1, wherein the tank is metal.
 3. The method of claim 1, wherein the membrane has a periphery, and wherein welding the spud and the membrane to the tank includes welding the spud to the periphery of the membrane.
 4. The method of claim 1, wherein the membrane is metal.
 5. The method of claim 1, wherein the membrane includes a substantially flat sheet of material.
 6. The method of claim 1, wherein the membrane has a thickness between about 0.002 inches and about 0.006 inches.
 7. The method of claim 1, wherein forming the second aperture includes removing at least a portion of the membrane.
 8. The method of claim 7, wherein removing at least a portion of the membrane includes inserting a hole saw through the threaded aperture of the spud, and cutting a substantially circular portion of the membrane.
 9. The method of claim 1, further comprising, subsequent to welding the spud and the membrane to the tank, applying an enamel coating to the interior of the tank while the membrane helps prevent the coating from contacting threads of the spud.
 10. The method of claim 9, wherein applying the coating includes applying one of porcelain, glass, and ceramic coatings to the interior of the tank.
 11. The method of claim 9, wherein applying the coating includes spraying unfired glass on the interior of the tank, and thereafter applying heat to the unfired glass.
 12. The method of claim 9, further comprising, subsequent to applying the coating to the interior of the tank, pressure testing the interior of the tank with the membrane covering the first aperture.
 13. The method of claim 1, further comprising, subsequent to welding the spud and the membrane to the tank, pressure testing the interior of the tank with the membrane covering the first aperture.
 14. The method of claim 1, wherein the tank is metal, wherein the membrane is metal and has a periphery, and wherein welding the spud and the membrane to the tank includes welding the spud to the periphery of the membrane.
 15. The method of claim 14, wherein the membrane includes a substantially flat sheet of material.
 16. The method of claim 15, wherein the membrane has a thickness between about 0.002 inches and about 0.006 inches.
 17. The method of claim 15, wherein forming the second aperture includes removing at least a portion of the membrane.
 18. The method of claim 17, wherein removing at least a portion of the membrane includes inserting a hole saw through the threaded aperture of the spud, and cutting a substantially circular portion of the membrane.
 19. A method of manufacturing a water heater, the method comprising: providing a water heater tank having an interior and an exterior, the tank also including a first aperture communicating between the interior and exterior; providing a spud having an internally threaded aperture; placing a membrane between the spud and the tank such that the membrane covers the first aperture; thereafter welding the spud and the membrane to the tank; thereafter spraying unfired glass to the interior of the tank; thereafter applying heat to the unfired glass; thereafter pressure testing the interior of the tank with the membrane covering the first aperture; and thereafter forming a second aperture in the membrane so that the threaded aperture of the spud communicates with the interior of the tank via the first and second apertures. 